This invention relates to wireless data communications systems and in particular relates to a system for providing communications between a mobile unit (MU) and an one or more access points (AP) of a network and also for providing data communications between a mobile unit and a peripheral device.
There are currently two models for short to moderate distance wireless data communications. Wireless local area networks, such as specified by IEEE specification 802.11, are essentially extensions of a wired local area network. In such systems there are access points that bridge packets between the wired and wireless networks. Mobile units have network interface cards (NIC's), frequently as a plug in device, to provide communications to the local area network via an access point. The network interface card may be PCMCIA cards, compact flash cards or integrated hardware located within the mobile unit. The network interface card and access point communicate with each other in order to move data packets between the wired network and the mobile unit.
Another form of wireless data communications is the personal area network, such as specified by IEEE standard 802.15/Bluetooth. Such networks are typically very short range, such as a few meters, and are used primarily for communications between a wireless peripheral device and a mobile unit, such as a mobile computer. In accordance with the Bluetooth system one unit functions as a master device and the other as a slave device. The master is usually a mobile unit, such as PDA or a notebook computer, while the slaves may be peripheral type devices, such as a printer, keyboard, mouse, scanner, etc.
Using existing technology, wireless local area networks (WLANs) are typically based on a standard such as IEEE 802.11, wherein mobile units become associated with access points and communicate with a wired network or a computer located on the wired network via the access point. The term “network” is intended to mean at least one computer connected for data communications to at least one access point. Personal area networks (PANs) on the other hand are usually based on a master/slave protocol, such as the Bluetooth protocol.
When it is desired to have a mobile unit communicate with both a wired network and a peripheral device, two distinct radios are required. The requirement for two radio systems adds cost and reduces the performance of both networks. It is known that the 802.11 and Bluetooth systems can interfere with each other, a fact that can only be partially compensated by using various “co-existence” algorithms. In addition, the use of two radios adds to the complexity, weight, and power requirements of a mobile unit.
As used in this application the term “Access point” is intended to include equivalent arrangements, such as that disclosed in copending application Ser. No. 09/528,697, filed Mar. 17, 2000, the specification of which is incorporated herein by reference, and is owned by the assignee of this application. As described in that application conventional 802.11 Access Points are replaced with a combination of an RF port and a cell controller, and wherein certain MAC functions of conventional access points are performed in the cell controller.
It is an object of the present invention to provide a method for data communications and an apparatus which provides both WLAN and PAN services using a single radio for both functions.